4.0 manual transmission, stalled then wouldn't start

Can anything be adjusted to accommodate this?
Truck is stalling when clutch is depressed even when not in gear.

 

Stalling when pedal is pushed in? Damn that's weird.


Not really much in the way of adjustments. There's a pushrod adjustment right at the clutch pedal but you really shouldn't be messing with that. The hydraulic system (Master/slave) is supposed to "self adjust" and take up the slack as the disc wears in. As long as nothing is leaking it should be good to go. Check the slave cylinder for fluid behind the boot and check for fluid leaking out of master cylinder and dribbling down the firewall inside the cabin

The bigger picture is the change in clutch engagement as things get hot. That really doesn't sound like a fluid issue. If fluid was leaking somewhere the symptom would stay that way until the leak is fixed or more fluid bled out. The fact that it goes back to normal (I'm assuming?) after things cool down kinda points to a mechanical issue with the clutch

 

Connection is tight. Hasn't been touched since truck was built, so aging a bit.

 

If anyone had recommended it, I would have had the mechanic replace the starter when the clutch was replaced. What a pain in the ass that job will be now!

 

The clutch generally engages higher than the stock clutch did. Perhaps I'm confusing whatever is causing the stall when I depress the clutch pedal with a change in engagement. I was having to rev the truck to keep it from stalling. And I was in deep spring snow. I was pushing a significant amount with the bumper, and I'm lifted 3" on 33s aired down to 10psi.

 

Yea, extra-ordinary conditions for sure. Asking a lot of the clutch..

I don't mean to confuse you and add on a bunch of possible scenarios. It's possible you just might have a intermittent bad starter and it fails when hot.

 

Starter is totally still on the table.
Stalling when clutch is depressed could be independent of potential impending failure of starter.

 

I got nothing as to what might be the actual cause, but this is an important piece of info... I'd start by looking at anything & everything that might've been R&R'ed for the clutch replacement (electrical connections, bleeding of the hydraulics, etc.). It's also quite possible there could be a combination of two or more issues in play here as well.

Keep us updated.

 

Yes, transmission is in neutral (I also tried in 1st gear, 4low).

I sent Uniclutch an email today.

 

This scenario is never recreated while driving on road, or off-road while not is snow but in a challenging area?

 

Not recreated on road in 2 weeks of daily driving. All challenging driving is under snow currently.

 

You sure the bellhousing isn't getting packed with snow?

This just seems super odd

 

Everything seems tight on the bell housing. I have a Pelfreybilt IFS skid on there, which should protect that area. I recently pulled my mid skid for resurfacing, and upcoming cat back exhaust replacement/ exhaust reroute for the case skid install.

 

Response from Uniclutch technical support engineer Damian S:

Hello

This particular issue you're experiencing is definitely a first and has never come up even in the development phase of the product.

As you can probably predict, there is no way how the stalling out of a motor would be caused by any fault of a clutch, they are 2 independent systems. Unless, of course, the clutch has failed catastrophically but the fact you're still able to drive the car after it has "cooled down" tells me the clutch is still functional.

Once the motor stalls out, what happens when you try to crank it? Have you tried to push start it when it dies? Do you have any struggle with gear selection?

I couldn't even say the internals are freezing over and locking up the driveline because you even mentioned yourself, it happens when the clutch gets hot. This is not something we can easily diagnose over email. I recommend removing the gearbox and checking for any abnormalities.
Regards

Damian S
Technical Support Engineer

My original email to them:

I recently had a Uniclutch Sport installed in my 2012 Toyota Tacoma roughly 1.5 months ago. It has recently developed an issue that my mechanic and I, and the internet, are having difficulties diagnosing.
When out on the trail, and working the clutch pretty hard, when the clutch gets hot the truck will stall when the clutch pedal is depressed. This occurs when the truck is not in gear and at idle or low rpm (I have to really rev it to keep this from happening). This has happened several times, multiple time in the same days.
When this happens, the truck also will not start. I have to let the truck sit and "cool down" (whether literally or not, I don't know) before it will start. Once I had to let it sit for over 30 minutes. Most times it needs between 2 and 5 minutes cool down time. All instances have been in deep snow offroading scenarios and relatively cold temperatures- anywhere from 20F to 40F (-7C to 5C?). I have an offroad trip to Moab planned in 2 weeks and would love to solve this issue and prove the worth of my Uniclutch to my friends who keep telling me I should have installed something else.

Thanks for your time, and your (hopefully) helpful response!

Dan

 

The issue of it shutting off when the clutch is depressed has to be tied to the clutch assembly or throw-out bearing. Those are the only areas that need to function to keep the vehicle running when the clutch is depressed. The good news is it'll be easier to replace the starter with the transmission off.

 

I'm in no rush to have the transmission pulled less than 2 months after having the clutch replaced. Throw out bearing was replaced at the same time. I just wish we had done the starter.

 

This connection doesn’t look good.

Disconnect the battery first. Take this nut off, clean the lug and its mating surface on the starter. Reassemble, see if the problem goes away.

 

@Key-Rei ideas?

 

Update
Just got back from Moab. Truck stalled after a very short crawl to a campsite that camper vans can drive to. Operating at low rpms seems to bring on the issue. It stalled again backing into a site at a campground on a level gravel pad. I was shifting into low range, and it stalled. Left it there and used the hi lift to get blocks under the tire to level it.
This time it threw a code. Twice. Cam position sensor. I cleared the code, but it still didn't start the first time. The next time I cleared the code, it started. The following morning, I left and drove to Idaho, and back to Montana the day after that. No issues.

I'm inclined to think I need a fuel pump.

 

What was the code number? When I had issues with one of my oil control valves the truck ran like shit at idle (but never stalled) and seemed to clear up somewhat after cooling off for a bit

I believe you should be running in open loop with those codes. And even if they cleared you should check for pending codes

OCV and CPS are real easy to change out. Not that Im suggesting you throw parts at it, but if that ends up being the case its an easy fix